Re: set the cost of an aggregate function

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: set the cost of an aggregate function
Date: 2009-12-03 12:19:03
Message-ID: 1259842743.13774.30895.camel@ebony
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On Mon, 2009-11-30 at 11:53 -0500, Jaime Casanova wrote:
> 2009/11/30 Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec>:
> > Hi,
> >
> > why we can't do $subject? it could have any benefit on the planner?
> >
>
> seems like while we can set the cost of the state transition function,
> that cost is not propagated...

The cost of comparison functions is not considered in cost_sort()
either.

The answer is nobody got round to enhancing this yet and well considered
proposals and subsequent patches would be welcome.

--
Simon Riggs www.2ndQuadrant.com

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